COMM5000 Excel Instructions: Final Report Modeling Contents 1 Data Preparation 2 2 Run the Regression (Data Analysis Toolpak) 2 3 Interpreting Output 2 4 Simulate a Prediction 2 5 Confidence and Prediction Intervals 2 6 Final Checklist 2 1 1 Data Preparation • Calculate Age: =2018 - [Year Built] • Log Price: =LN([Market Price]) • Create Dummy Variables: – =IF([State] = "VIC", 1, 0) for State VIC – Repeat for State QLD, Structure Brick Veneer, etc. 2 Run the Regression (Data Analysis Toolpak) • Go to Data > Data Analysis > Regression • Set Y Range as Log(Price), and X Range as your predictors • Check Labels, Confidence Level = 95%, and specify Output Range 3 Interpreting Output • Use coefficients to interpret marginal effects • Approximate percentage change: 100× coefficient • Review Adjusted R-squared and F-test p-value 4 Simulate a Prediction 1. Input new values for a scenario (e.g., 3 beds, 2 baths, 80 sqm car area) 2. Multiply each input value by its respective coefficient: =Coeff * Value 3. Sum results and add intercept: =SUMPRODUCT(inputs, coefficients) + Intercept 4. Convert to price: =EXP(predicted log price) 5 Confidence and Prediction Intervals • Use CONFIDENCE.T(0.05, StandardError, n) • Add/subtract from predicted log price to form CI • Add residual standard error to CI bounds to form PI • Exponentiate bounds: =EXP(lower), =EXP(upper) 6 Final Checklist Dummy variables created Log(Price) calculated Regression run and interpreted Prediction scenario simulated CI and PI computed and converted to price scale Workbook is clear and formulas traceable 2
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